1,1,2-trichloroethylene conductivity

Halogenated hydrocarbons depress cardiac contractility, decrease heart rate, and inhibit conductivity in the cardiac conducting system. The cardiac-toxicity of these compounds is related to the number of halogen atoms it increases first as the number of halogen atoms increases, but decreases after achieving the maximum toxicity when four halogen atoms are present. Some of these compounds, e.g., chloroform, carbon tetrachloride, and trichloroethylene, sensitize the heart to catecholamines (adrenaline and noradrenaline) and thus increase the risk of cardiac arrhythmia. 

Although catalytic wet oxidation of acetic acid, phenol, and p-coumaric acid has been reported for Co-Bi composites and CoOx-based mixed metal oxides [3-5], we could find no studies of the wet oxidation of CHCs over supported CoO catalysts. Therefore, this study was conducted to see if such catalysts are available for wet oxidation of trichloroethylene (TCE) as a model CHC in a continuous flow fixal-bed reactor that requires no subsequent separation process. The supported CoOx catalysts were characterized to explain unsteady-state behavior in activity for a certain hour on stream. 

A retrospective case-control study conducted in humans compared spontaneous abortion rates among women who had been exposed occupationally or nonoccupationally to trichloroethylene and other solvents to rates among women without solvent exposure (Windham et al. 1991). The authors observed approximately three times the risk of spontaneous abortion with exposure to trichloroethylene. This risk increased further when women with less than a half hour of exposure to trichloroethylene each week were excluded from the analysis. However, a consistent dose-response relationship was not observed, and most of the women were exposed to a variety of solvents, not just trichloroethylene. 

Several retrospective cohort studies of workers exposed to unquantified levels of trichloroethylene have been conducted. All of these studies have limitations that restrict their usefulness for evaluating the carcinogenicity of trichloroethylene. None has shown clear, unequivocal, evidence that trichloroethylene exposure is linked to increased cancer risk. 

Experiments were conducted in which purified trichloroethylene (1 mg in acetone) was applied to the shaved backs of female ICR/Ha Swiss mice (Van Duuren et al. 1979). In an initiation-promotion study, a single application of trichloroethylene was followed by repeated application of phorbol myristate acetate (PMA) promoter. In a second study, mice were treated with trichloroethylene three times per week without a promoter. No significant tumor incidences were observed in these studies. Doses used in these studies were well below the maximum tolerated dose, which is often not reached in dermal studies. 

In a comprehensive study of trichloroethylene emission sources from industry conducted for EPA, the major source was degreasing operations, which eventually release most of the trichloroethylene used in this application to the atmosphere (EPA 1985e). Degreasing operations represented the largest source category of trichloroethylene emissions in 1983, accounting for about 91% of total trichloroethylene emissions. Other emission sources include relatively minor releases from trichloroethylene manufacture, manufacture of other chemicals (similar chlorinated hydrocarbons and polyvinyl chloride), and solvent evaporation losses from adhesives, paints, coatings, and miscellaneous uses. 

The National Occupational Exposure Survey (NOES), conducted by NIOSH from 1981 to 1983, estimated that 401,000 workers employed at 23,225 plant sites were potentially exposed to trichloroethylene in the United States (NOES 1990). The NOES database does not contain information on the frequency, concentration, or duration of exposures the survey provides only estimates of workers potentially exposed to chemicals in the workplace. 

Exposure Levels in Humans. This information is necessary for assessing the need to conduct health studies on these populations. Trichloroethylene has been detected in human body fluids such as blood (Brugnone et al. 1994 Skender et al. 1994) and breast milk (Pellizzari et al. 1982). Most of the monitoring data have come from occupational studies of specific worker populations exposed to trichloroethylene. More information on exposure levels for populations living in the vicinity of hazardous waste sites is needed for estimating human exposure. 

Group A5 Not suspected as a human carcinogen. Trichloroethylene is not suspected to be a human carcinogen on the basis of properly conducted epidemiologic studies in humans. 

Triebig G, Reichenbach TH, Flugel KA. 1978. [Biochemical examinations and measurements of the conduction velocity in persons chronically exposed to trichloroethylene.] Int Arch Occup Environ Health 42 31-40. (German)... 

The technology has proven effective in bench-scale tests for the treatment of trichloroethylene (TCE), dichloroethane (DCA), and p-nitrophenol (PNP) and can potentially treat a variety of organic, inorganic, and mixed wastes. Bench-scale and pilot-scale field tests have been conducted, and further testing of the Lasagna process is in progress. 

In a 1995 treatability study conducted for the U.S. Department of Energy (DOE) Savannah River facility, a cost estimate was prepared for an FTO system with a flow rate of 400 standard cubic feet per minute (scfm) using natural gas to maintain process temperatures. Costs were estimated at 0.72/lb. For the purposes of this estimate, the inlet concentration was assumed to be 400 ppm of trichloroethylene (TCE), perchloroethylene (PCE), and 1,1,1-trichloroethane (TCA). Capital costs were estimated at 160,000. Capital costs were amortized over 10 years, not over the time required to remediate the site. This cost estimate found FTO to be more cost effective than thermal catalytic technologies due to lower operating and maintenance costs (D125122, p. 10). 

The analytes separated on GC column are determined by a halogen-specific detector, such as an electrolytic conductivity detector (ELCD) or a microcoulo-metric detector. An ECD, FID, quadrupole mass selective detector, or ion trap detector (ITD) may also be used. A photoionization detector (PID) may also be used to determine unsaturated halogenated hydrocarbons such as chlorobenzene or trichloroethylene. Among the detectors, ELCD, PID, and ECD give a lower level of detection than FID or MS. The detector operating conditions for ELCD are listed below ... 

U.S. and one industrial waste water treatment in Spain. Engineering scale field experiments have been conducted by the National Renewable Energy Laboratory (NREL) at the Lawrence Livermore National Laboratory (LLNL) treating ground water contaminated with trichloroethylene (TCE) [253]. This field system consisted of 158 m2 of parabolic trough reactors and used De-gussa P25 particles (0.1%) as the photocatalyst in a slurry flow configuration. With this relatively low titanium dioxide content the TCE concentration was reduced from 200 ppb to less than 5 ppb. 

Metabolomics has made remarkable inroads into the environmental research community. Here, a major emphasis is to understand the impact that environmental stress, such as pollution and climate change, has on wildlife. Indeed, many government organizations monitor the prevalence of pollutants in certain species of wildlife as indicators of the exposure risk within the environment. Studies of Japanese medaka have been conducted to investigate the effects of trichloroethylene, a common environmental pollutant, and the pesticide dinoseb, on the development of fish embryos (44, 45). Similarly, cadmium toxicity has been examined in the bank vole and rat and has revealed changes in lipid metabolism that preceded classical nephrotoxicity (46, 47). Another study investigated the effects of environmental toxins on earthworms (48). In particular, the analysis of earthworm tissue extracts by NMR spectroscopy identified maltose as a potential biomarker for ecotoxicity within a metal-contaminated site. 

Most research work on the use of supercritical water has been conducted batchwise and involved non-analytical determinative applications. Thus, supercritical water oxidation (SCWO) was proposed as an alternative treatment for hazardous waste disposal [191] and also as a commercial tool for decomposing trichloroethylene, dimethyl sulphoxide and isopropyl alcohol on a pilot plant scale [192]. Current commercially available equipment (the aqua Critox" system) is usable with industrial and municipal sludge, mixed (radioactive and organic, liquid and solid) waste and military waste. This commercially available treatment has a number of advantages, namely (a) because it uses an on-site treatment method, it avoids the need to transport hazardous materials (b) it ensures complete destruction of organic wastes and allows reuse of the effluent as process water with results that meet the regulations for drinking water and (c) no licence for effluent or air emissions is needed. 

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